风积沙混凝土盐冻损伤规律与机理分析

Damage and mechanism analysis of aeolian sand concrete under the salts corrosion and freeze-thaw

利用加速试验方法研究了风积沙混凝土在腐蚀与冻融双因素作用条件下的损伤规律,并借助气泡间距分析仪(analyzer of air void spacing,AVS)、环境电镜扫描(environmental scanning electron microscope,ESEM)和核磁共振(nuclear magnetic resonance,NMR)微观测试手段得到了风积沙混凝土的损伤失效机理。结果表明,在盐腐蚀与冻融循环双因素作用下,风积沙混凝土的损伤程度依次为复合盐>硫酸盐>氯盐,但在3种盐溶液中冻融的损伤机理不同;在盐溶液中,风积沙掺量越大,抗冻性能越好。该研究为风积沙混凝土在低温盐腐蚀的环境中大范围推广使用提供理论依据。

The frost and corrosion resistance of six types of aeolian sand concretes were studied through accelerated test method in three salt solution,and finally the damage laws of ordinary concrete and aeolian sand concrete were demonstrated.In addition,the damage mechanism of aeolian sand concrete under freeze thaw and salt corrosion conditions was analyzed by using the testing measures such as,environmental scanning electron microscope(ESEM),analyzer of air void spacing,and nuclear magnetic resonance(NMR),etc.This result indicated that aeolian sand concrete is subjected to freeze-thaw in the salt solution,and the damage degree of concrete decreases in the order according to sodium sulfate and sodium chloride compound solution,sodium sulfate solution and sodium chloride solution.But the damage mechanism of freeze thaw in3kinds of salt solution is different.Besides,in salt solution,the greater the amount of aeolian sand,the better the frost resistance.It provides theoretical basis for the aeolian sand concrete widespread application,the research of aeolian sand concrete under the influence of complex factors in low temperature and salt corrosion environment.